Image processing apparatus

ABSTRACT

An image apparatus that is connected to an outer apparatus and transmits image data to the outer apparatus, having therein; a generating means that generates binarized image data, an acquiring means that acquires the outer apparatus resolution data showing resolution of data which can be processed by the outer apparatus, a calculating means that calculates an image resolution data showing resolution of the image data, and calculates a reduction rate based on the image resolution data and on the outer apparatus resolution data, a dividing means that divides the image data into a plural matrixes in accordance with the reduction rate, a gradation judgment means that judges gradation of each matrix, a distinction means that recognizes a line-work in the image data and distinguishes whether pixels constituting the recognized line-work are present in each matrix or not, a gradation determining means that determines gradation after image processing in each matrix based on results of gradation judgment and on results of distinction, and an image processing means that replaces all pixels in each the matrix with one pixel having gradation determined by the gradation determining means to convert the image data and generates reduced data.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an image processing apparatusthat conducts reduction processing of image data.

[0002] As an image processing apparatus conducting reduction processingof image data, there have so far been devised an apparatus that thinsout pixels constituting image data, an apparatus that determinesgradation of reduced pixels through logic operation of looked pixels andsurrounding pixels and reduces image data, and an apparatus to reduceimage data by utilizing an optical system when reading image data. Therehas further been devised an image processing apparatus that reads imagedata on a multi-valued basis, and generates reduced images by conductingmulti-valued operation when outputting the image data.

[0003] However, in the image processing apparatus employing theaforesaid method to thin out pixels simply, fine line-works sometimesbecome blurred to be scratchy although density of image data can be keptby pseudo-continuous tone, because error diffusion is conducted. On theother hand, in the image processing apparatus wherein there is conductedlogic operation of looked pixels and surrounding pixels, if the logic toleave information of dense gradation is selected, there is caused aproblem that density of image data is made to be high entirely bypseudo-continuous tone, although line-works are not broken. Further, inthe case of an image processing apparatus to reduce optically, whenoutputting to an outer apparatus having high resolution, reduced imagedata have been enlarged for outputting, and image quality has beendeteriorated accordingly, which has been a problem. Further, in the caseof an image processing apparatus that processes image data on amulti-valued basis, when preserving image data converted on amulti-valued basis, necessary memory capacity is increased, comparedwith an occasion for preserving binarized data, resulting in a problemof high cost and necessity of improvement.

SUMMARY OF THE INVENTION

[0004] The subject of the invention is to provide an image processingapparatus and an image processing method wherein line-work and gradationare preserved when image data are reduced, and image quality of imagedata outputted to an outer apparatus having high resolution is notdeteriorated, and cost is low.

[0005] The invention is provided with the following structure to solvethe aforesaid subjects.

[0006] The present invention is represented by an image apparatus thatis connected to an outer apparatus and transmits image data to the outerapparatus, having therein; a generating means that generates binarizedimage data, an acquiring means that acquires, from the outer apparatus,resolution data of the outer apparatus showing resolution of data whichcan be processed by the outer apparatus, a calculating means thatcalculates an image resolution data showing resolution of said imagedata, and calculates a reduction rate based on said image resolutiondata and on said outer apparatus resolution data, a dividing means thatdivides said image data into a plurality of matrixes in accordance withsaid reduction rate, a gradation judgment means that judges gradation ofeach matrix stated above, a distinction means that recognizes aline-work in the image data and distinguishes whether pixelsconstituting the recognized line-work are present in each matrix statedabove or not, a gradation determining means that determines gradationafter image processing in each matrix based on results of gradationjudgment conducted by the gradation judgment means and on results ofdistinction conducted by the distinction means, an image processingmeans that replaces all pixels in each said matrix with one pixel havinggradation determined by the gradation determining means to convert theimage data and generates reduced data and an output means that outputsthe image data or the reduced data.

[0007] The present invention makes it possible to preserve an originalline-work of image data and to keep the gradation when reducing theimage data. Further, since image data are binarized in the invention, itis possible to save the memory to be used, compared with the imageprocessing that employs multi-valuing, and thereby to provide aninexpensive image processing apparatus, and it is further possible toreduce an amount of data in the case of transmitting image data to anouter apparatus, and thereby to increase transmission speed. Inaddition, since reduced data and image data before reduction areselected to be transmitted, according to the resolution of an outerapparatus to which the image data are outputted, image data beforereduction can be outputted to the other party having high resolution,which makes it possible to provide image data having less deteriorationof image quality.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is a diagram showing the total structure of image providingsystem 100 in the present embodiment.

[0009]FIG. 2 is a block diagram showing functional structures of imageprocessing apparatus 1 shown in FIG. 1.

[0010]FIG. 3 is a flow chart showing image data reduction processing byimage processing apparatus 1 shown in FIG. 1.

[0011]FIG. 4 is a diagram illustrating a concrete example of image datareduction processing.

DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of the invention will be explained in detail asfollows, referring to FIGS. 1-4. In the above Structure and in thefollowing embodiment, in this case, a line-work means a linear imagesuch as, for example, a straight line and a curved line. Further, theouter apparatus resolution shows resolution of data that can beprocessed by the outer apparatus, and the image resolution data meandata showing resolution of image data. Incidentally, facsimileresolution data in the following embodiment correspond to the outerapparatus resolution data described in the Structure stated above.Further, image processing apparatus 1 and facsimile 2 in the followingembodiment respectively have functions as the image processing apparatusand the outer apparatus in the above Structure.

[0013] The structures will be explained, first.

[0014]FIG. 1 is a diagram showing the over-all structure of imageproviding system 100 in the present embodiment. As shown in FIG. 1, theimage providing system 100 is structured in a way that image processingapparatus 1 equipped with image reading section 17 and facsimile 2 areconnected each other through network N so that both of them may transmitand receive data.

[0015] Incidentally, in FIG. 1, there is shown an example wherein a unitof image processing apparatus 1 and a unit of facsimile 2 are connectedthrough network N, and the number of units of these apparatuses in notlimited in particular. Further, an outer apparatus connected to theimage processing apparatus 1 is not limited to facsimile 2, and its typeis not limited, provided that the outer apparatus can process image dataand is equipped with a communication function.

[0016] The image processing apparatus 1 is equipped with image readingsection 17 (see FIG. 1) that reads image data, and is connected withfacsimile 2 through network N. In reduction processing for image data,the image processing apparatus 1 binarizes images read from imagereading section 17 and generates image data, then, calculates thereduction rate for image data based on image resolution data showingresolution of image data and on facsimile resolution data showingresolution of facsimile 2, and converts image data with the calculatedreduction rate to generate reduced data. Further, image processingapparatus 1 has facsimile communication function to transmit reduceddata generated in image data reduction processing to facsimile 2 throughnetwork N.

[0017] The facsimile 2 is connected with the image processing apparatus1 through network N, and is equipped with facsimile communicationfunction to transmit and to receive text data and image data, and withfunction to process the data mentioned above. The facsimile 2 displaysimage data obtained from the image processing apparatus 1 on anunillustrated display section, or prints from an unillustrated printingmechanism. Incidentally, let it be assumed that resolution of data thatcan be processed by the facsimile 2 of the present embodiment is lowerthan that of image data read by the image processing apparatus 1.

[0018] Incidentally, data showing resolution in facsimile 2 are calledfacsimile resolution data, data read by the image processing apparatus 1and binarized are called image data, data showing resolution of imagedata are called image resolution data, and data reduced by the imageprocessing apparatus 1 are called reduced data.

[0019] The network N is a communication network structured by usingprivate lines or general public lines, and various line forms such asLAN or WAN can be applied to the communication network. In the networkN, there are included, for example, various communication line networkssuch as telephone lines network, ISDN line network, private linenetwork, mobile communication network, communications satellite linesand CATV line network, and Internet service provider that connects theforegoing. Further, although an example wherein respective apparatusesare connected by wire is shown in FIG. 1, wireless connection can alsobe used. From the viewpoint of reliability of information management,however, it is preferable that-the network has security that allows onlyspecific users to access.

[0020] The structure of image processing apparatus 1 will be explainedin detail as follows, referring to FIG. 2.

[0021]FIG. 2 is a block diagram showing the functional structure of theimage processing apparatus 1. As shown in FIG. 2, the image processingapparatus 1 is composed of control section 11, input section 12, displaysection 13, communication control section 14, RAM 15, storage section16, image reading section 17, counter 18, pixel quantity comparingsection 19, image conversion section 20 and image processing section 21,and each section is connected to others through bus 22.

[0022] The control section 11 is composed of CPU (Central ProcessingUnit) and others, and it reads system programs stored in the storagesection 16 and various control programs to develop them in RAM 15, andcontrols operations of each section intensively according to the controlprogram. Further, the control section 11 conducts various types ofprocessing in accordance with the program developed in RAM 15, andcauses the results of the processing to be stored in RAM 15 temporarilyand to be displayed on the display section 13. To be concrete, thecontrol section 11 reads image data reduction processing program fromthe storage section 16, and conducts image data reduction processingwhich will be described later. Further, in the image data reductionprocessing, it transmits to facsimile 2 the reduction data generatedbased on resolutions of both images and facsimile 2, through network N.

[0023] In the image data reduction processing, when image read fromimage reading section 17 is inputted, the control section 11 makes thisimage to be binarized in the image conversion section 20 and makes imagedata to be generated. It further calculates image resolution data of thebinarized image data, and acquires facsimile resolution data fromfacsimile 2 through network N to calculate the reduction rate based onthe image resolution data and the facsimile resolution data. Thereduction rate to be calculated here is one to convert image data andthereby to generate reduction data having the same resolution as in thefacsimile resolution data.

[0024] Further, in the image data reduction processing, the controlsection 11 calculates the number of pixels of the image data necessaryfor generating one pixel of reduction data, based on the calculatedreduction rate mentioned above, and divides image data by the matrixcomposed of the calculated number of pixels. Further, the controlsection 11 makes the counter 18 to count the number of black pixels foreach divided matrix, and makes the pixel quantity comparing section 19to compare the number of black pixels inputted from the counter 18 withthe threshold value established in advance to acquire the results of thecomparison. When the number of black pixels in the matrix is greaterthan the threshold value in this case, all pixels in the matrix arereplaced with on black pixel. On the other hand, When the number ofblack pixels in the matrix is not greater than the threshold value, thecontrol section 11 reads line-work conditions from the storage section16 for reference, and recognizes the pixels constituting line-work inthe image data. Then, when pixels constituting the line-work are presentin the matrix, the control section 11 replace all pixels in the matrixwith on black pixel, while, when the pixels are not present, all pixelsin the matrix are replaced with on white pixel.

[0025] Namely, the control section 11 has functions as various meanssuch as a dividing means, a gradation judgment means, a gradationdetermining means and a calculating means.

[0026] The input section 12 includes a key board equipped with a cursorkey, a numeral input key and various types of functional keys, andoutputs depression signals corresponding to keys depressed on the keyboard to the control section 11. Incidentally, the input section 12 mayalso be provided with a pointing device such as a mouse or a touch paneland with other input devices, as occasion demands.

[0027] The display section 13 is composed of LCD (Liquid CrystalDisplay) and CRT (Cathode Ray Tube), and displays thereon inputinstructions coming from the input section 12 and data, in accordancewith instructions of display signals inputted from the control section11.

[0028] The communication control section 14 is composed of LAN adaptor,a router and TA (Terminal Adaptor), and conducts control of thecommunication with each apparatus connected to network N throughcommunication lines such as private lines or ISDN lines. Further, thecommunication control section 14 transmits facsimile resolution datareceived from facsimile 2 through network N to the control section 11,and transmits reduction data generated by image data reductionprocessing to facsimile 2 in accordance with instructions from thecontrol section 11.

[0029] Namely, the communication control section 14 has functions as anoutput means and an acquiring means.

[0030] In each processing conducted and controlled by the controlsection 11, RAM (Random Access Memory) 15 forms a tentative storage areafor system program, control program, input or output data and parameterwhich are read from storage section 16 and can be executed on imageprocessing apparatus 1.

[0031] The storage section 16 has a recording medium (not shown) onwhich programs and data are stored in advance, and this recording mediumis composed of a magnetic or optical recording medium, or of asemiconductor memory. This recording memory is one provided fixedly onstorage section 16, or one mounted detachably, and a system programcorresponding to server 1, various types of processing programscorresponding to the system programs and data of the results of theprocessing are stored in this recording medium. These programs invarious types are stored in the form of a readable program code, and thecontrol section 11 conducts successively the operations which conform tothe program code.

[0032] To be concrete, the storage section 16 stores image datareduction processing program used in image data reduction processing,line-work conditions and results of image data reduction processing. Theline-work conditions in this case mean conditions for recognizingline-work in image data. For example, a condition of a line-work inimage data is that black pixels are continuous for 10×10 pixels or morein both directions of the main scanning direction and sub-scanningdirection. Incidentally, this line-work condition is not limited to thenumerical value (10×10 pixels).

[0033] The image reading section 17 is composed of a contact glass onwhich a photograph or an original is placed and of a scanner positionedbelow the contact glass, and it reads information of images of thephotograph or the original. The scanner is composed of a light source, alens and CCD (Charge Coupled Diode), and it forms an image from lightthat is applied from a light source on a photograph or an original andis reflected, then, it reads images by converting themphotoelectrically, and transmits information of the images thus read toimage conversion section 18 in accordance with instructions from thecontrol section 11.

[0034] The counter 18 counts black pixels in each matrix of image datadivided by the control section 11 in the image data reductionprocessing, and outputs the results of counting to pixel quantitycomparing section 19.

[0035] The pixel quantity comparing section 19 compares the results ofcounting to be inputted from the counter 18, namely, the number of blackpixels with the threshold value established in advance, and outputs theresults of the comparison to the control section 11. Namely, the pixelquantity comparing section 19 has a function as a gradation judgmentmeans.

[0036] The image conversion section 20 converts images inputted from theimage reading section 17 into binary image data. Namely, the imageconversion section 20 has a function as a generating means.

[0037] The image processing section 21 conducts various types of imagedata processing such as frequency processing and gradation processing onthe inputted image data, in accordance with instructions inputted fromthe control section 11. Further, image processing section 17 conductscompression processing that compresses by means of the prescribed codingmethod, and extension processing that decodes the compressed image datato extend. It further generates reduction data by replacing pixels ineach matrix in image data with one black or white pixel, based on theinstruction coming from the control section 11.

[0038] Namely, the image processing section 21 has a function as animage processing means.

[0039] Next, operations will be explained as follows.

[0040] As an assumption for explanation of operations, programs forrealizing respective processing described in the flow chart in FIG. 3are stored in storage section 16 in the form of program code that can beread by the computer, and the control section 11 conducts successivelythe operations conforming to the aforesaid program code.

[0041]FIG. 3 is a flow chart showing image data reduction processingconducted by the control section 11 of the image processing apparatus 1in FIG. 1. As shown in FIG. 3, when images read from the image readingsection 17 are inputted, the control section 11 judges that imagereading has been completed (step S1; YES) and makes the inputted imagesto be binarized by the image conversion section 20 to generate imagedata (Step S2). Then, the control section 11 judges if the facsimileresolution data are stored in storage section 16 (step S3), and when thedata are stored (step S3; YES), the flow moves to step S5, while whenthe data are not stored (step S3; NO), the control section 11 acquiresfacsimile resolution data from communication control section 14 throughnetwork N (step S4), and moves to step S5.

[0042] Then, the control section 11 calculates image resolution data ofthe binarized image data and calculates the reduction rate for the imagedata based on image resolution data and facsimile resolution data (stepS5). After that, in accordance with the calculated reduction rate, thecontrol section 11 calculates the number of pixels of image data whichhave not been reduced and are needed to generate one pixel of thereduced data, and divides image data with a matrix composed of thecalculated number of pixels (step S6). Next, the number of black pixelsexisting in each divided matrix is counted in the counter 18, then, thecounted number of black pixels is compared with a threshold value bypixel quantity comparing section 19, and the result of comparison of thenumber of pixels in the matrix is obtained (step S7).

[0043] After that, when the result of distinction by the pixel quantitycomparing section 19 is inputted from image reading section 17, thecontrol section 11 reads line-work conditions from storage section 16when the number of black pixels in the matrix is not greater than thethreshold value (step S8; NO), then, it recognizes pixels constituting aline-work in image data (step S9), and judges if the pixels constitutinga line-work are included in each matrix (step S10), and when the pixelsconstituting a line-work are not included (step S10; NO), all pixels inthe matrix are replaced with one white pixel by image processing section21 (step S11), and the flow moves to step S13.

[0044] On the other hand, when the number of black pixels in the matrixis greater than the threshold value in the step S8 (step S8; YES) andwhen pixels constituting a line-work are present in the matrix (stepS10; YES), all pixels in the matrix are replaced with one black pixel byimage processing section 21 (step S12), and the flow moves to step S13.

[0045] In step S13, the control section 11 judges if replacement ofpixels has been terminated in all matrixes, and when the replacement hasnot been terminated (step S13; NO), the flow moves back to step S7,while, if the replacement has been terminated (step S13; YES), imagedata reduction processing is terminated.

[0046] After completion of the image data reduction processing, thecontrol section 11 transmits the generated reduced data to facsimile 2from communication control section 14 through network N, and stores thereduced data and image data before reduction in storage section 16.

[0047] Now, image data reduction processing will be explained moreconcretely with reference to FIG. 4.

[0048]FIG. 4 is a diagram illustrating a concrete example of image datareduction processing. In the drawing, there are shown image data (anupper portion in the drawing) generated from images obtained throughreading by image reading section 17 of image processing apparatus 1 andreduced data (a lower portion in the drawing). In this case, let it beassumed that resolution of the image data is 600×600 dpi and resolutionof facsimile 2 is 200×200 dpi, and a threshold value in the pixelquantity comparing section 19 is 4, and neither matrix A nor matrix Bshown in the drawing includes pixels constituting a line-work.

[0049] In the example shown in FIG. 4, the reduction rate for image datais ⅓ based on image resolution data and facsimile resolution data, andthe control section 11 divides image data in a way that an amountequivalent to three pixels in each of the main scanning direction andthe sub-scanning direction of image data, namely, an amount equivalentto nine pixels form a matrix. The control section 11 makes the counter18 to count the number of black pixels in matrix A (number of blackpixels 4), then, replaces nine pixels in matrix A with one white pixelbecause the number of black pixels is not more than the threshold valueafter the result of comparison by the pixel quantity comparing section19, and forms one pixel of reduced data shown with A′. With respect tomatrix B, nine pixels in the matrix B are replaced with one black pixelbecause the number of black pixels is 5 which is greater than thethreshold value, and one pixel of reduced data shown with B′ isgenerated.

[0050] In the image data reduction processing, the control section 11generates image data by binarizing images read, and calculates imageresolution data to calculate the reduction rate based on facsimileresolution data and the calculated image resolution data. Then, thecontrol section 11 calculates the number of pixels of image datanecessary to generate one pixel of reduced data based on the calculatedreduction rate, and divides image data into a matrix calculated based onthe calculated number of pixels. The number of black pixels in thedivided matrix is compared with the established threshold value in thepixel quantity comparing section 19, and when the number of black pixelsis not more than the threshold value, and no pixels constituting aline-work are included in the matrix, all pixels in the matrix arereplaced with one white pixel, and in other cases, reduced data aregenerated by replacing all pixels in the matrix with one black pixel.Further, the control section 11 provides reduced data to facsimile 2 bymeans of communication control section 14 through network N.

[0051] In reducing image data, therefore, it is possible to preserve anoriginal line-work of image data and to preserve gradationsimultaneously. Since image data are binarized, it is possible to savememories to be used and to cut manufacturing cost for image processingapparatus 1, compared with image processing by means of multi-valuing.It is further possible to increase transmission speed without outputtingexcessive data, because reduced image data are outputted to an outerapparatus in accordance with resolution of the outer apparatus to beconnected.

[0052] Incidentally, in the aforesaid embodiment, image processingapparatus 1 is connected to facsimile 2 having resolution that is lowerthan that of image data which are read by image processing apparatus 1to output reduced data in accordance with facsimile resolution data.However, when the image processing apparatus 1 is connected to an outerapparatus having high resolution other than the facsimile 2, and whenthis outer apparatus has resolution that is equal to or higher than thatof image data, it is naturally possible to transmit image data whichhave not been subjected to reduction processing to the outer apparatusas they are. In this method, it is possible to avoid deterioration ofimage quality of image data caused by enlargement or reductionprocessing, and to provide more clear data to the outer apparatus.

[0053] Further, in the aforesaid embodiment, detailed structures of theimage processing apparatus 1 and detailed operations may be modifiedappropriately, without deviating from the spirit of the invention.

[0054] The present invention makes it possible to preserve an originalline-work of image data and to keep the gradation when reducing theimage data. Further, since image data are binarized in the invention, itis possible to save the memory to be used, compared with the imageprocessing that employs multi-valuing, and thereby to provide aninexpensive image processing apparatus, and it is further possible toreduce an amount of data in the case of transmitting image data to anouter apparatus, and thereby to increase transmission speed. Inaddition, since reduced data and image data before reduction areselected to be transmitted, according to the resolution of an outerapparatus to which the image data are outputted, image data beforereduction can be outputted to the other party having high resolution,which makes it possible to provide image data having less deteriorationof image quality.

What is claimed is:
 1. An image processing apparatus, connected to anouter apparatus and transmits image data to said outer apparatus,comprising: a generating means for generating binarized image data; anacquiring means for acquiring, from said outer apparatus, said outerapparatus resolution data showing resolution of data to be processed bysaid outer apparatus; a calculating means for calculating an imageresolution data, showing resolution of said image data, and forcalculating a reduction rate based on said image resolution data and onsaid outer apparatus resolution data; a dividing means for dividing saidimage data into a plurality of matrixes in accordance with saidreduction rate, a gradation judgment means for judging gradation of eachof said matrixes; a distinction means for recognizing a line-work insaid image data so as to distinguish whether pixels, constituting saidline-work, are present in each of said matrixes or not; a gradationdetermining means for determining gradation, after image processing ineach of said matrixes, based on results of gradation judgment by saidgradation judgement means and on results of distinction by saiddistinction means; and an image processing means for replacing allpixels in each of said matrixes with one pixel, having gradationdetermined by said graduation determining means, to convert said imagedata to generate reduced data.
 2. The image processing apparatus ofclaim 1, further comprising: an output means for outputting said imagedata or said reduced data.